The objectives of this project are to provide direct evidence of the effects of H1 phosphorylation on higher order structure in chromatin, and to attempt to determine the mechanism of activation of the growth-associated protein kinase that catalyzes H1 phosphorylation at the time of mitosis in dividing cells. Procedures for the reconstitution of chromatin with H1 and phosphorylated forms of H1 will be developed. The fidelity of reconstitution and the effects of H1 molecules phosphorylated to different levels and containing phosphate in specific sites will be assessed by techniques of nuclease digestion, sedimentation, thermal denaturation and, in collaboration with others, neutron scattering and electric birefringence. The growth-associated protein kinase will be purified to homogeneity from both interphase and mitotic cells in attempts to identify two interconvertible forms of this enzyme and to establish the mechanism of interconversion. (K)